Saulius Gražulis

> I am fine with including support for H-M symbols and symmetry operators, and I volunteer to prepare PR(s) whenever the details about them are sorted out. I forgot to...

> Are you opposed to IT number + an optional field `origin_choice` I'm quite strongly opposed to this combination – it does not solve the symmetry operator issue, is not...

> (I'm aware of the investigation of @sauliusg and @BobHanson that concluded that there are origin choices that cannot be represented as Hall symbols, but that is not ambiguity.) I...

> While I really like to follow the CIF standard when we can, I'm not overly enthusiastic over the `_space_group_symop_operation_xyz` format, because it is very verbose and non-canonical. If anything...

To sum up, I propose the following two options for the upcomming PR: 1. If we want to keep OPTIMADE standard simple and just use the bare minimum, we standardise:...

> Serving up Cartesians with symmetry operations (necessarily fractional) seems odd to me. Indeed it is odd; good point! > - For anyone wanting to convert back from Cartesians to...

> - Personally, I would prefer ITA number + H-M + operations. The ITA number and H-M would both be valuable for searches I agree. Does this mean that we...

> There is also option 3: > > 3. IT number, symops list and **one** of [Hall, HM, Schönflies] symbols (the same one for all databases). But what should we...

> @sauliusg > > > As I understand, the fractional coordinates were discussed but not yet described. > > Should we make an issue for this? > > There is...

> This was the first place where we realized that "just adding support also for fractional coordinates" was taking us in a direction where databases could choose to support either...